If the problem is the keyboard isn't allowing you to type, try the information below. However if the problem is the password, then you need to contact whatever company you have the modem/router through for password assistance. We cannot assist in bypassing any passwords. Please read the following thread...
http://www.tomsguide.com/forum/id-2317968/read-passwords-lock-codes-pin-numbers.html
Again, if it is the keyboard that is the issue, try the following...
1. Uninstall the keyboard driver.
2. Reboot the computer (without reinstalling the driver).
3. When it restarts, it should reinstall the driver on its own.
If this doesn't work, you may wish to try connecting/reconnecting an external keyboard and see if it works fine. If it does, then it could be the keys themselves that are the issue.
You may also want to try updating the Synaptics Driver if the above doesn't help.